This invention relates to a high frequency electronic cooking device and more particularly to a microwave oven provided with an improved turntable support member.
Generally, in a high frequency electronic cooking device, a foodstuff to be cooked is heated by microwave energy generated from a magnetron and/or radiant heat from electric heaters.
The electronic cooking device of this type generally comprises a box-shaped cabinet, a control panel and an oven door which are arranged on the front side of the cabinet, a heating chamber located inside the oven door and defined by an oven frame, a waveguide provided at its one end with a port opened at the top wall of the heating chamber, a magnetron coupled to the other end of the waveguide, and a flat rotary disc on which a turntable is removably mounted. A pair of electric heaters are horizontally located in the heating chamber to heat the foodstuff mounted on the turntable from the upper and lower sides. An electric motor for driving the rotary disc is disposed below the bottom wall of the heating chamber through a drive shaft which extends into the oven through bearings provided at the central portion of the bottom wall.
In a typical known cooking device, the turntable is supported by the flat rotary disc in frictional engagement or in engagement with projections formed on the rotary disc and grooves formed on the rear surface of the turntable. In addition, in some cases a plurality of rollers are disposed on the bottom wall of the heating chamber so as to rotatably support the rotary disc and prevent undesired wobbling motion thereof. However, various problems have been encountered in these supporting structures when it is desired to exactly position the turntable on the rotary disc while rotating, firmly support same, and maintain the oven in a clean state after the heating operation, which disadvantages will be described in detail hereinafter with reference to accompanying drawings. Moreover, there is a problem that the foodstuff is not sufficiently and evenly heated for the reason that the electromagnetic waves concentrate at the edge portion of the flat rotary disc.
In order to obviate these disadvantages, there has been proposed an improved rotary support member in which the rotary disc is formed as a dish shaped member provided with through holes. However, this prior art design can also not positively support the turntable and uniformly heat the foodstuff on the turntable.